RESUMEN
Adverse reactions (ARs) during the infusion of cellular therapy products (CTPs) are common in patients undergoing hematopoietic stem cell transplantation (HSCT). We retrospectively studied pediatric patients undergoing autologous and allogeneic HSCT to determine the incidence and grade of ARs during stem cell infusion and their predictors. We analyzed data from 213 patients (120 allogeneic and 93 autologous) who received at least 1 CTP, totaling 361 infusion episodes. Serious ARs, defined as grade 2 and 3, occurred in 25 and 11% of infusions, respectively. No grade 4 or 5 ARs were noted. Independent risk factors for developing a serious AR included stem cell source (PBSC vs marrow (odds ratio (OR) 1.8, 95% confidence interval (CI): 0.4-9); cord vs marrow (OR 7.3, 95% CI: 1.3-40), overall P=0.0001) but manipulated CTPs were protective (OR 0.4, 95% CI: 0.2-0.7, P=0.004). Unlike previous adult studies, WBC and granulocyte content were not found to be risk factors in this pediatric population. These data suggest that children tolerate higher WBC content during infusion of CTPs and support the use of manipulated CTP, as indicated, to reduce the risk of adverse infusion reactions.
Asunto(s)
Trasplante de Células Madre/efectos adversos , Niño , Preescolar , Femenino , Granulocitos , Humanos , Leucocitos , Masculino , Estudios Retrospectivos , Factores de Riesgo , Trasplante de Células Madre/estadística & datos numéricos , Células Madre/citología , Trasplante Autólogo , Trasplante HomólogoRESUMEN
A clinical field investigation was conducted to evaluate the safety and efficacy of 10% imidacloprid/2.5% moxidectin for the treatment of ear mites (Otodectes cynotis) in dogs. The study was a multi-centered, blinded, positive controlled, randomized clinical trial conducted under field conditions with privately owned pets. A total of 17 veterinary clinics enrolled cases for the study. An otoscopic examination was performed to confirm the presence of O. cynotis residing in the ear of the dog prior to enrollment. A single-dog household was enrolled in the study if the dog had 5 or more ear mites and an acceptable physical examination. A multi-dog household was eligible if at least one dog in the household had 5 or more mites and all dogs in the household had acceptable physical exams and met the inclusion criteria. Qualified households were randomly assigned to treatments to receive either 10% imidacloprid+2.5% moxidectin topical solution or topical selamectin solution (positive control product) according to a pre-designated enrollment ratio of 2:1, respectively. If more than one dog in a multiple dog household had adequate numbers of ear mites, one dog was randomly selected to represent the household for efficacy evaluation prior to treatment. Treatments were administered twice per label and dose banding directions for each product approximately 28 days apart (Days 0 and 28), by the dog's owner at the study site. All dogs in a household were treated on the same day and with the same product. The owners completed a post-treatment observation form one day after each treatment. Post-treatment otoscopic examinations were performed by the investigators or attending veterinarian on Days 28 and 56. Physical examinations were performed on Days 0 and 56. One hundred and four (104) households were evaluated for efficacy on SD 28, and 102 households were evaluated for efficacy on SD 56. The dogs' ages ranged from 2 months to 16 years. A total of 247 dogs were evaluated for safety. Percent efficacy was based on the percentage of dogs cleared of ear mites. Mite clearance on Day 28 was 71% for the imidacloprid+moxidectin group and 69% for the selamectin group. Mite clearance on Day 56 was 82% for the imidacloprid+moxidectin group and 74% for the selamectin group. No serious adverse events associated with either product were observed during the study. The study demonstrated that 10% imidacloprid+2.5% moxidectin applied using two topical treatments, 28 days apart, was safe and achieved similar efficacy against O. cynotis as selamectin treatments applied and evaluated under the same conditions.
Asunto(s)
Enfermedades de los Perros/parasitología , Enfermedades del Oído/veterinaria , Imidazoles/uso terapéutico , Macrólidos/uso terapéutico , Infestaciones por Ácaros/veterinaria , Nitrocompuestos/uso terapéutico , Animales , Enfermedades de los Perros/tratamiento farmacológico , Perros , Combinación de Medicamentos , Enfermedades del Oído/parasitología , Imidazoles/administración & dosificación , Insecticidas/administración & dosificación , Insecticidas/uso terapéutico , Ivermectina/análogos & derivados , Ivermectina/uso terapéutico , Macrólidos/administración & dosificación , Neonicotinoides , Nitrocompuestos/administración & dosificaciónRESUMEN
We investigated the effects of the selective NK(3) tachykinin receptor antagonist, SB-235375, on noxious signalling from gut and skin and on intestinal motility in anaesthetized rats. We also measured penetrance into brain and spinal cord. Nociceptive responses in reaction to colorectal distension and skin pinch were assessed by recording the electromyogram (EMG) from the external oblique muscle (a visceromotor response). Motility was measured by recording intraluminal pressure waves during changes in baseline pressure in the jejunum. Colorectal compliance was assessed by measuring luminal pressure change during isovolumic distension. SB-235375 (20 mg kg(-1), by i.v. bolus) reduced the EMG response to colorectal distension by over 90%. The reduction was slow at onset, peaked at about 60 min, and lasted for over 2 h. Responses to noxious skin pinch were unchanged. Amplitudes of propulsive waves in the jejunum were slightly reduced, but their frequency of occurrence was unchanged. SB-235375 decreased colorectal compliance by 5-10%. There was undetectable penetration of i.v. SB-235375 into brain or spinal cord. We conclude that SB-235375 acts peripherally to substantially reduce nociceptive signalling from colorectum without affecting noxious signalling from skin and with little effect on intestinal motility.
Asunto(s)
Acetatos/farmacología , Motilidad Gastrointestinal/efectos de los fármacos , Intestinos/fisiología , Dolor/fisiopatología , Quinolinas/farmacología , Receptores de Neuroquinina-3/antagonistas & inhibidores , Acetatos/análisis , Acetatos/farmacocinética , Anestesia , Animales , Barrera Hematoencefálica/fisiología , Electromiografía , Sistema Nervioso Entérico/fisiología , Intestinos/efectos de los fármacos , Masculino , Nociceptores/efectos de los fármacos , Nociceptores/fisiología , Quinolinas/análisis , Quinolinas/farmacocinética , Ratas , Ratas Sprague-Dawley , Piel/inervaciónRESUMEN
Experiments were carried out in rats to (1) elaborate upon the sepcificity of drug action in the periaqueductal gray matter (PAG), and (2) to evaluate the posible congruence of PAG sites of morphine-induced and stimulation-produced analgesis (SPA) applied at virtually identical PAG loci. It was demonstrated that the effect of morphine intracerebrally (i,c.) administered into the PAG was not duplicated by other centrally acting agents (chlorpromazine, chlordiazepoxide, pentobarbital or naloxone) administered i.c. at the same PAG site. This selective action of morphine in the PAG was further demonstrated not to be test-bound since morphine significantly altered responding in all four of the analgesiometric tests employed. Thus, multiple i.c. injections of drugs at the same PAG locus were useful in demonstrating site specificity of drug action where behavioral and electroencephalographic methods alone had previously provided ambiguous information. Morphine-induced analgesia and SPA, evaluated at virtually coincident PAG sites, revealed only a general congruence of efficacious loci. The most effective PAG loci for morphine-induced analgesia were not the same as those for SPA; analgesia effected by one analgesia-producing manipulation did not reliably predict that analgesia would also be produced by the other analgesia-producing manipulation at the PAG sites examined. In general, the more efficacious analgesia-producing PAG loci were localized in the ventral-ventrolateral PAG.
Asunto(s)
Analgesia , Acueducto del Mesencéfalo/efectos de los fármacos , Morfina/farmacología , Receptores Opioides/análisis , Animales , Clordiazepóxido/farmacología , Clorpromazina/farmacología , Relación Dosis-Respuesta a Droga , Masculino , Naloxona/farmacología , Pentobarbital/farmacología , RatasRESUMEN
5-HT4 receptors are concentrated in areas of the brain which are rich in dopamine neuronal markers, which may suggest that they influence motor and reward processes. We tested this hypothesis by examining the effects of a 5-HT4 receptor antagonist, 8-amino-7-chloro-(N-butyl-4-piperidyl)methylbenzo-1,4-dioxan-5-car boxylate hydrochloride (SB-204070-A) on amphetamine- and nicotine-induced locomotor stimulation in intact rats. In rats with unilateral 6-hydroxydopamine-induced lesions of the ascending nigrostriatal dopaminergic projection, SB-204070-A was tested for its effects on amphetamine-induced rotation. SB-204070-A was also tested for its effects on rewarded behaviour maintained by intracranial self-stimulation. SB-204070-A did not alter behaviour under any of these conditions, suggesting a lack of involvement of the 5-HT4 receptor in motor and reward processes.
Asunto(s)
Conducta Animal/efectos de los fármacos , Dioxanos/farmacología , Actividad Motora/efectos de los fármacos , Piperidinas/farmacología , Antagonistas de la Serotonina/farmacología , Anfetamina/farmacología , Animales , Cocaína/farmacología , Hipercinesia/inducido químicamente , Masculino , Nicotina/farmacología , Ratas , Ratas Sprague-Dawley , Autoestimulación/efectos de los fármacosRESUMEN
For progression to clinical trials in stroke, putative neuroprotective compounds should show robust efficacy post-ischaemia in several experimental models of stroke. This paper describes the characterisation of (+)(1S, 2R)-cis-1-[4-(1-methyl-1-phenylethyl)phenoxy]-2-methylamino indane hydrochloride (SB-221420-A), a Ca(2+) and Na(+) channel antagonist. SB-221420-A inhibited (IC(50)=2.2 microM) N-type voltage-operated Ca(2+) channel currents in cultured superior cervical ganglion neurons, which were pretreated with 10 microM nimodipine to block L-type voltage-operated Ca(2+) channel currents. In dorsal root ganglion neurons pretreated with 1 microM omega-conotoxin GVIA to block N-type voltage-operated Ca(2+) channel currents, SB-221420-A inhibited the residual Ca(2+) current with an IC(50) of 7 microM. SB-221420-A also inhibited Na(+) currents in dorsal root ganglion neurons with an IC(50) of 8 microM. In rats, the pharmacokinetic profile of SB-221420-A shows that it has a half-life of 6.4 h, a high volume of distribution, is highly brain penetrating, and has no persistent metabolites. Following bilateral carotid artery occlusion in gerbils, SB-221420-A significantly reduced the level of ischaemia-induced hyperlocomotor activity and the extent of hippocampal CA1 cell loss compared to the ischaemic vehicle-treated group. SB-221420-A was also effective in focal models of ischaemia. In the mouse permanent middle cerebral artery occlusion model, SB-221420-A (10 mg/kg) administered intravenously, post-ischaemia significantly (P<0.05) reduced lesion volume compared to the ischaemic vehicle-treated group. In the normotensive rat permanent middle cerebral artery occlusion model, SB-221420-A (10 mg/kg) administered intravenously over 1 h, beginning 30 min postmiddle cerebral artery occlusion, significantly (P<0.05) reduced lesion volume from 291+/-16 to 153+/-30 mm(3), compared to ischaemic vehicle-treated controls when measured 24 h postmiddle cerebral artery occlusion. Efficacy was maintained when the same total dose of SB-221420-A was infused over a 6-h period, beginning 30 min postmiddle cerebral artery occlusion. SB-221420-A also significantly (P<0.05) reduced lesion volume following transient middle cerebral artery occlusion in normotensive rats and permanent middle cerebral artery occlusion in spontaneously hypertensive rats (SHR). Investigation of the side effect profile using the Irwin screen in mice revealed that, at neuroprotective doses, there were no overt behavioural or cardiovascular changes. These data demonstrate that robust neuroprotection can be seen post-ischaemia with SB-221420-A in both global and focal ischaemia with no adverse effects at neuroprotective doses, and indicate the potential utility of a mixed cation blocker to improve outcome in cerebral ischaemia.
Asunto(s)
Bloqueadores de los Canales de Calcio/farmacología , Indanos/farmacología , Fármacos Neuroprotectores/farmacología , Bloqueadores de los Canales de Sodio , Accidente Cerebrovascular/prevención & control , Anestesia , Animales , Animales Recién Nacidos , Encéfalo/efectos de los fármacos , Encéfalo/patología , Estenosis Carotídea/fisiopatología , Estenosis Carotídea/prevención & control , Células Cultivadas , Estado de Conciencia , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Gerbillinae , Hemodinámica/efectos de los fármacos , Hipertensión/fisiopatología , Indanos/farmacocinética , Infarto de la Arteria Cerebral Media/patología , Infarto de la Arteria Cerebral Media/prevención & control , Ataque Isquémico Transitorio/fisiopatología , Ataque Isquémico Transitorio/prevención & control , Masculino , Potenciales de la Membrana/efectos de los fármacos , Tasa de Depuración Metabólica , Ratones , Actividad Motora/efectos de los fármacos , Neuronas Aferentes/citología , Neuronas Aferentes/efectos de los fármacos , Neuronas Aferentes/fisiología , Ratas , Ratas Endogámicas SHR , Ratas Sprague-Dawley , Accidente Cerebrovascular/fisiopatología , Distribución TisularRESUMEN
The efficacy of reduced intensity conditioning (RIC) allogeneic hematopoietic cell transplantation (HCT) for Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL) is uncertain. We analyzed 197 adults with Ph+ ALL in first complete remission; 67 patients receiving RIC were matched with 130 receiving myeloablative conditioning (MAC) for age, donor type and HCT year. Over 75% received pre-HCT tyrosine kinase inhibitors (TKIs), mostly imatinib; 39% (RIC) and 49% (MAC) were minimal residual disease (MRD)(neg) pre-HCT. At a median 4.5 years follow-up, 1-year transplant-related mortality (TRM) was lower in RIC (13%) than MAC (36%; P=0.001) while the 3-year relapse rate was 49% in RIC and 28% in MAC (P=0.058). Overall survival (OS) was similar (RIC 39% (95% confidence interval (CI) 27-52) vs 35% (95% CI 27-44); P=0.62). Patients MRD(pos) pre-HCT had higher risk of relapse with RIC vs MAC (hazard ratio (HR) 1.97; P=0.026). However, patients receiving pre-HCT TKI in combination with MRD negativity pre-RIC HCT had superior OS (55%) compared with a similar MRD population after MAC (33%; P=0.0042). In multivariate analysis, RIC lowered TRM (HR 0.6; P=0.057), but absence of pre-HCT TKI (HR 1.88; P=0.018), RIC (HR 1.891; P=0.054) and pre-HCT MRD(pos) (HR 1.6; P=0.070) increased relapse risk. RIC is a valid alternative strategy for Ph+ ALL patients ineligible for MAC and MRD(neg) status is preferred pre-HCT.
Asunto(s)
Trasplante de Médula Ósea , Neoplasia Residual , Cromosoma Filadelfia , Leucemia-Linfoma Linfoblástico de Células Precursoras/cirugía , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Inducción de Remisión , Tasa de Supervivencia , Acondicionamiento Pretrasplante , Adulto , Animales , Femenino , Cobayas , Humanos , Masculino , Persona de Mediana Edad , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Trasplante Homólogo , Adulto JovenRESUMEN
Although the role of autologous hematopoietic cell transplantation (auto-HCT) is well established in neuroblastoma (NBL), the role of allogeneic HCT (allo-HCT) is controversial. The Center for International Blood and Marrow Transplant Research conducted a retrospective review of 143 allo-HCT for NBL reported in 1990-2007. Patients were categorized into two different groups: those who had not (Group 1) and had (Group 2) undergone a prior auto-HCT (n=46 and 97, respectively). One-year and five-year OS were 59% and 29% for Group 1 and 50% and 7% for Group 2, respectively. Among donor types, disease-free survival (DFS) and OS were significantly lower for unrelated transplants at 1 and 3 years but not at 5 years post HCT. Patients in CR or very good partial response (VGPR) at transplant had lower relapse rates and better DFS and OS, compared with those not in CR or VGPR. Our analysis indicates that allo-HCT can cure some neuroblastoma patients, with lower relapse rates and improved survival in patients without a history of prior auto-HCT as compared with those patients who had previously undergone auto-HCT. Although the data do not address why either strategy was chosen for patients, allo-HCT after a prior auto-HCT appears to offer minimal benefit. Disease recurrence remains the most common cause of treatment failure.
Asunto(s)
Trasplante de Células Madre Hematopoyéticas/métodos , Neuroblastoma/cirugía , Adolescente , Adulto , Niño , Preescolar , Recolección de Datos , Supervivencia sin Enfermedad , Enfermedad Injerto contra Huésped/etiología , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Humanos , Lactante , Persona de Mediana Edad , Estudios Retrospectivos , Tasa de Supervivencia , Trasplante Autólogo , Trasplante Homólogo , Resultado del Tratamiento , Adulto JovenRESUMEN
Hodgkin lymphoma (HL) is cured in the majority of children and adolescents. However, there remains a group of patients with primary refractory or relapsed disease for whom cure is more difficult to achieve. Most of these patients receive high-dose chemotherapy followed by auto-SCT, with expected cure rates ranging from 40 to 60%. Conditioning regimens often consist of multiple non-cross-resistant agents, with well-described risks of morbidity and mortality. The use of single-agent high-dose melphalan (HDM) as conditioning, before autologous rescue, has been described in adult patients at our center, with comparable efficacy and less morbidity. We present a series of eight pediatric patients conditioned with single-agent HDM before autologous stem cell rescue for relapsed and primary refractory HL. All patients engrafted with a median of 12 days to neutrophil engraftment. Two patients subsequently relapsed. Seven patients are currently alive, and seven of eight patients have no evidence of disease (one in CR3). Toxicities included grade 4 hematologic in 8/8, grade 3 mucositis in 3/8, grade 3 infectious in 2/8 and grade 4 infectious in 1/8. Our analysis suggests that this regimen is feasible in pediatric patients with acceptable engraftment and toxicity.
Asunto(s)
Enfermedad de Hodgkin/tratamiento farmacológico , Enfermedad de Hodgkin/terapia , Melfalán/administración & dosificación , Agonistas Mieloablativos/administración & dosificación , Trasplante de Células Madre/métodos , Adolescente , Canadá , Niño , Resistencia a Antineoplásicos , Femenino , Humanos , Linfoma/terapia , Masculino , Melfalán/farmacología , Agonistas Mieloablativos/farmacología , Recurrencia , Estudios Retrospectivos , Acondicionamiento Pretrasplante/métodosRESUMEN
Although reduced-intensity conditioning (RIC) and non-myeloablative (NMA)-conditioning regimens have been used for over a decade, their relative efficacy vs myeloablative (MA) approaches to allogeneic hematopoietic cell transplantation in patients with AML and myelodysplasia (MDS) is unknown. We compared disease status, donor, graft and recipient characteristics with outcomes of 3731 MA with 1448 RIC/NMA procedures performed at 217 centers between 1997 and 2004. The 5-year univariate probabilities and multivariate relative risk outcomes of relapse, TRM, disease-free survival (DFS) and OS are reported. Adjusted OS at 5 years was 34, 33 and 26% for MA, RIC and NMA transplants, respectively. NMA conditioning resulted in inferior DFS and OS, but there was no difference in DFS and OS between RIC and MA regimens. Late TRM negates early decreases in toxicity with RIC and NMA regimens. Our data suggest that higher regimen intensity may contribute to optimal survival in patients with AML/MDS, suggesting roles for both regimen intensity and graft vs leukemia in these diseases. Prospective studies comparing regimens are needed to confirm this finding and determine the optimal approach to patients who are eligible for either MA or RIC/NMA conditioning.
Asunto(s)
Trasplante de Células Madre Hematopoyéticas/métodos , Leucemia Mieloide Aguda/terapia , Síndromes Mielodisplásicos/terapia , Acondicionamiento Pretrasplante/métodos , Adolescente , Adulto , Anciano , Supervivencia sin Enfermedad , Femenino , Humanos , Leucemia Mieloide Aguda/cirugía , Masculino , Persona de Mediana Edad , Síndromes Mielodisplásicos/cirugía , Trasplante Homólogo , Resultado del Tratamiento , Adulto JovenAsunto(s)
Suero Antilinfocítico/administración & dosificación , Busulfano/administración & dosificación , Trasplante de Células Madre Hematopoyéticas/métodos , Leucemia Mielomonocítica Juvenil/terapia , Agonistas Mieloablativos/administración & dosificación , Acondicionamiento Pretrasplante/métodos , Vidarabina/análogos & derivados , Irradiación Corporal Total/métodos , Preescolar , Terapia Combinada , Humanos , Lactante , Leucemia Mielomonocítica Juvenil/tratamiento farmacológico , Vidarabina/administración & dosificaciónAsunto(s)
Analgésicos/farmacología , Animales , Aspirina/farmacología , Reacción de Prevención/efectos de los fármacos , Conducta Animal/efectos de los fármacos , Clordiazepóxido/farmacología , Clorpromazina/farmacología , Evaluación Preclínica de Medicamentos/métodos , Etanol/farmacología , Hidroxibutiratos/farmacología , Ketamina/farmacología , Masculino , Ratones , Morfina/farmacología , Naloxona/farmacología , Pentobarbital/farmacología , Oxibato de SodioRESUMEN
In children with acute lymphoblastic leukemia (ALL) with isolated central nervous system (CNS) relapse and a human leucocyte antigen (HLA)-matched sibling, the optimal treatment after attaining second remission is unknown. We compared outcomes in 149 patients enrolled on chemotherapy trials and 60 HLA-matched sibling transplants, treated in 1990-2000. All patients achieved a second complete remission. Groups were similar, except the chemotherapy recipients were younger at diagnosis, less likely to have T-cell ALL and had longer duration (> or = 18 months) first remission. To adjust for time-to-transplant bias, left-truncated Cox's regression models were constructed. Relapse rates were similar after chemotherapy and transplantation. In both treatment groups, relapse rates were higher in older children (11-17 years; RR 2.81, P=0.002) and shorter first remission (< 18 months; RR 3.89, P<0.001). Treatment-related mortality rates were higher after transplantation (RR 4.28, P=0.001). The 8-year probabilities of leukemia-free survival adjusted for age and duration of first remission were similar after chemotherapy with irradiation and transplantation (66 and 58%, respectively). In the absence of an advantage for one treatment option over another, the data support use of either intensive chemotherapy with irradiation or HLA-matched sibling transplantation with total body irradiation containing conditioning regimen for children with ALL in second remission after an isolated CNS relapse.
Asunto(s)
Antineoplásicos/uso terapéutico , Trasplante de Médula Ósea/métodos , Neoplasias del Sistema Nervioso Central/terapia , Histocompatibilidad , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Adolescente , Neoplasias del Sistema Nervioso Central/etiología , Niño , Preescolar , Recolección de Datos , Supervivencia sin Enfermedad , Femenino , Antígenos HLA , Humanos , Infiltración Leucémica/etiología , Infiltración Leucémica/terapia , Estudios Longitudinales , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Radioterapia/métodos , Recurrencia , Inducción de Remisión , Hermanos , Acondicionamiento Pretrasplante/métodos , Resultado del TratamientoRESUMEN
An electrolytic approach to cutting small-diameter stainless steel tubing is described. The method is superior to abrasion or manual methods because it produces a clear lumen in the smallest diameter tubing available. The method is simple, quick, and inexpensive and has been found valuable for making small injection needles, small tissue punches, and for repairing broken or occluded microliter syringes.
Asunto(s)
Electrólisis , Inyecciones/instrumentación , Acero Inoxidable , Animales , Cateterismo/instrumentación , Perros , JeringasRESUMEN
Two experiments are reported with young Down's syndrome and normal children matched for mental age, sex, and social class. In one, Down's syndrome children performed at chance level on two tactual--visual cross-modal tasks, and only the oldest succeeded with one of two visual--visual within-modal tasks. The modal children performed at above chance level on the visual--visual tasks, and on the tactual--visual tasks the oldest succeeded on two and the youngest on one of the tasks. These results suggest that Down's syndrome children may have some sort of difficulty involving tactual perception. The second experiment examined the effect of touch on visual behaviour. Down's syndrome children and their matched controls looked at pairs of shapes which sometimes could be touched and sometimes could not. In the former condition the Down's syndrome children touched less, and looking and touching was less coordinated than that of normal children. However, both groups made fewer but longer looks when they could touch the shapes. In the light of these results the role of tactual perception in Down's syndrome children is discussed.
Asunto(s)
Síndrome de Down/psicología , Tacto , Percepción Visual , Factores de Edad , Atención , Desarrollo Infantil , Preescolar , Humanos , Lactante , Psicología Infantil , Desempeño PsicomotorRESUMEN
Investigation of children's understanding of the cognitive verb forget has shown that young children do not consider the role of prior knowledge when using this verb. Thus, someone may be said to have forgotten a fact despite not ever having previously known it. However, forget can also be used to refer to a failure to recall a prior intention. Three experiments examined the role of prior intention as well as prior knowledge in the comprehension of forget by 160 young children aged four to eight years. The results showed that children initially have two interpretations of forget: as an unfulfilled desire rather than a failure to recall a prior intention, and as a state of not knowing rather than a failure to recall prior knowledge. Explanations for the late comprehension of forget are discussed in terms of representation of knowledge and intention, processing capacity and exposure to pragmatic usages.
Asunto(s)
Cognición , Aprendizaje Verbal , Vocabulario , Factores de Edad , Niño , Preescolar , HumanosRESUMEN
Children's narratives consist of event clauses and contextualizing or 'evaluative' clauses. Bamberg & Damrad-Frye (1991) and Bamberg (1994) claimed that young children make limited use of evaluative clauses because they are less able to adopt a global perspective on the narrative. In an earlier study, Karmiloff-Smith (1985) demonstrated that the narratives of younger children have coherence only at a local level. However, Wellman & Bartsch (1988) showed that young children could produce evaluative-like causal explanations if given a specific prompt. The present study on 160 young children aged five, seven, nine and eleven years examined their production of evaluatives in narratives of a story presented as a video sequence with no spoken dialogue, to ensure that the children's production was not simply a re-working of verbal input. Results indicated that prompts greatly facilitated children's production of evaluatives and that they could adopt a global perspective on the story when formulating evaluatives. These results indicate that limitations in the narratives of young children are more plausibly explained by contextual factors influencing language production and by constraints on working memory than by children's presumed lack of understanding of the structure of events or their inferences about the minds of the characters.
Asunto(s)
Lenguaje Infantil , Lenguaje , Habla , Conducta Verbal , Grabación en Video , Niño , Preescolar , Femenino , Humanos , Masculino , Distribución AleatoriaRESUMEN
Macrophages, granulocytes and many lymphocytes express or secrete receptors for the Fc domain of immunoglobulins (Ig). These Fc receptors (FcRs) are heterogeneous and can be distinguished on the basis of their cellular distribution and specificities for different immunoglobulin isotypes. Although their functions are not completely understood, FcRs are known to be involved in triggering various effector cell functions and in regulating differentiation and development of B-cells. One of the best characterized is the mouse macrophage-lymphocyte receptor for IgG1 and IgG2b (ref. 5). On macrophages, this FcR mediates the endocytosis of antibody-antigen complexes via coated pits and coated vesicles, the phagocytosis of Ig-coated particles, and the release of various inflammatory and cytotoxic agents. It is possible that the receptor possesses an intrinsic ligand-activated ion channel activity responsible for some of these functions. The IgG1/IgG2b FcR has been isolated and shown to be a transmembrane glycoprotein of relative molecular mass (Mr) 47,000-60,000 (47-60 K) containing four N-linked oligosaccharide chains and a large (greater than 10K) cytoplasmic domain. It is also immunologically indistinguishable from the murine Ly-17 alloantigen which, in turn, is tightly linked to the Mls lymphocyte activation locus. Here we describe the isolation and characterisation of a complementary DNA clone encoding the whole of the IgG1/IgG2b FcR expressed by the mouse macrophage-like cell line P388D1. The receptor is a member of the immunoglobulin superfamily and, like Ly-17, maps to the distal portion of chromosome 1. cDNA probes detect one or two mRNA species in FcR+ macrophage and B-cell lines, but not in FcR- cells or a receptor-deficient variant derived from a FcR+ B-cell line. Finally, DNA hybridization analysis indicates the receptor gene is partially deleted or rearranged in the FcR- variant.
Asunto(s)
Clonación Molecular , ADN/metabolismo , Linfocitos/inmunología , Macrófagos/inmunología , Receptores Fc/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Línea Celular , Enzimas de Restricción del ADN , Ratones , ARN Mensajero/genéticaRESUMEN
The murine t-complex encodes t-complex polypeptide-1 (TCP1), which is constitutively expressed in almost all cells, and upregulated during spermatogenesis. Mammalian sequences have greater than 96% identity with each other, and greater than 60% identity with Drosophila melanogaster and yeast orthologues. TCP1 is essential in yeast, and is postulated to be the cytosolic mammalian equivalent of groEL. We report here that, in the native state, murine and human TCP1 is distributed throughout the cytosol as an 800K-950K hetero-oligomeric particle in association with four to six unidentified proteins and two Hsp70 heat-shock proteins. Negative-stain electron microscopy indicates that the structure is two stacked rings, 12-16 nm in diameter. Therefore, despite similarities with the chaperonin 60 proteins, these data indicate that TCP1 is biochemically and structurally unique. We suggest that TCP1 may represent one of a family of molecules in the eukaryotic cytosol involved in protein folding and regulated in part by their heteromeric associations.